Process for cracking hydrocarbon oils



Nov. 24, 1 931.

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Nov. 24, 1931. G. EGLoFF E1' AL Y PROCESS FOR CRACKING HYDROCARBON OILS Original Filed Aug. 20, 1920 5 Sheets-Sheet 2 @Bvb .Sat

G. EGLoFF E1' AL PROCESS FOR CRACKING HYROCARBON OILS Patented Nov. 24, 1931 UNITED STATES PATENT oFFlcE GUSTA'V EGLOFF AND HARRY P. BENNER, CHICAGO, ILLINOIS, ASSIGNORS TO UNI- VERSAL OIL PRODUCTS COMPANY, 0F CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA PROCESS FOR CRACKING HYDROCARBON OILS Application led August 20, 1920. Serial No. 404,912.

This invention relates to a process for treating heavy petroleum oils, such as the residual products obtained in the distillation of petroleum, whereby such heavy oils are converted by means of heat and pressure into lighter oils such as gasoline, kerosene, gas oil or the like.

Among the salient objects of theinvention are to provide a process in which relatively heavy or residual oils, as for example, fuel oil from petroleum, are cracked in a so-called vcontinuous process,.in such a way as to avoid clogging up or injuring the apparatus by carbon deposition, particularly in that part 0f the apparatus which is subjected to more or less direct heat action while at the same time obtaining a maximum yield of gasolene with minimum fuel consumption; to provide a process of the character referred to in which a maximum amount of charging stock is fed through the apparatus in a given unit of time and with relation to the area of heating surface in the fire zone While at the sa-me time permitting a maximum predetermined production of gasolene or the like hvdrocarbon desired to be produced; to p-rovide a process of the character in question which Will produce gasoline-like bodies from such residual oil at the rate of at least 2O percent per hour of the charging stock: to provide a process of the character referred to which treats in excess of one gallon of charging oil per square foot of heating surface in the fire zone per hour, or in other words. permits of feeding the residual oil through the fire zone at a rate of not less than 200 gallons of residualoil per hour for every 200 square feet of heating area. While at the same time producing gasolene at the rate aforementioned: to provide a process in which the residual oil is cracked to the extent of converting and removing from the vapor chambern the for-m of vapor in excess of 50 percent of the oil charged per hour; to provide a process of the character ,aforesaid in which regulatable proportions of said vapors and more particularly the heavier parts thereof are condensed and collected separatelv from the lighter parts there- 'such gasolene like bodies; to provide a processof the character in question in which the residual oilis converted into gasolene like bodies and distillation products in which the latter in effect constitute acharging stock which is continuously being produced simultaneously With the gasolene like bodies referred to; to provide a process for cracking residual oil whereby there is provided pressure distillate which contains less unsaturated hvdrocarbons than the original residual oil which formed the charging stock: to provide a process in which heavy residual oil, as for example, fuel oil or petroleum tarmay be converted into gasolene, kerosene and gas oil iii-varying percentages, as for example: 19 to 32 percent `rrasolene, 8 to 14 percent kerosene,

11 to 20 percent gas oil, to provide a process of cracking the residual oil or petroleum tar referred to, in which the oil is so treated in the heating or fire zone that only a negligible amount of carbon is precipitated in the heating tubes or more specifically, the carbon so precipitated may not be more than 0 03 lbs. per gallon of oil charged through the heating tubes; to provide a process in which the fuel oil or petroleum tar referred to may be converted into the light hydrocarbons hereinabove mentioned at a relatively low fuel cost;

process; to provide a pressure distillate produced by the cracking of petroleum tar,

which pressure distillate has a lower percentage of unsaturated hydrocarbons than'the petroleum tar from which it was produced, and in general to provide improvements of the cb aracter hereinafter set forth.

Before describing the apparatus in which We may carry out our inventionq it may be noted that our process has heretofore been carried out in commercial operation in the treatment of petroleum tars produced as a,

and the Delaware field of Oklahoma. It may also be noted that these residual oils were between 21.6 and 24.3 Baume gravity. These petroleum tars are also known and sold as fuel oils, and for fluxes for hard asphalts, and certain of the asphaltic constituents which are sometimes recovered by further distillation at atmospheric pressure, and by oxidation. By the petroleum tar is also included such natural heavy oils as heavy Mexican and California crudes which are more or less devoid of the lighter hydrocarbons herein desired to be produced.

By no known prior process has it been possible to commercially crack the petroleum tars or residual oils above referred to; one principal objection being that oils of this character produce such large amounts of carbon, it has not been commercially feasible to crack them. By our process we avoid the precipitation or formation of carbon in that p ortion of the apparatus in which the charging oil is brought to cracking temperature and pressure. And, it may be noted in this connection that the oil while passing through the heating or fire zone is preferably maintained in the liquid phase.

In the drawings:

Fig. 1 is a vertical sectional view of the furnace construction and apparatus mounted therein.

Fig. 2 is a side elevation of the apparatus.

Fig. 3 is an end elevation.

Before describing the apparatus in detail a general statement of the essential features of the apparatus and process may be given. The fuel oil is fed by means of a charging pump into a continuous coil of say 4-inch pipe suitably separated within a furnace. The arrangement is such that the fuel oil may be heated at a pressure of 50 pounds upwards to a cracking temperature. The fuel oil while still in the liquid phase is transferred to a vapor chamber of sufficient size to readily take care of the precipitated carbon which in the illustration given'in the drawings takes the form of a coil of pipe 10 inches in diameter. The vapors pass out of the vapor chamber through suitable risers and are then subjected first to an initial or reflux condensing action and then to a final or complete condensation. The reflux condensation is so controlled as to condense the heavier portions of the vapor which may be subjected to further cracking reactions. In the present instance the reflux condensate is continuously returned to the charging line and mixed with afresh charging stock. The lighter vapors are condensed by the second or final condensation. The unvaporized p0rtion of the oil which enters the vapor chamber is drawn off, preferably continuously, and in such a manner as to keep the carbon in suspension to the greatest possible extent in the oil which is being so drawn off. In this connection it may be here noted that it is highly desirable to keep the residue from gettin too heavy and thus concentrating and precipitating the carbon in the vapor chamber instead of removing it with the drawn off residuum. This is accomplished by regulating the gravity of the residue leaving the vapor'chamber.

Describing now more in detail, 1 designates the furnace having Dutch oven 2 and burners 3. In the furnace or firing zone are supported the heating elements which in the present instance take the form of a coil of four inch tubes 4 having return bends 5. The furnace is equipped with the usual stack 6. 7 designates the inlet for the charging oil which is connected to the charging pump 7. In the present instance the heating element comprises 14 tubes, each of four inches inteinal diameter and twenty feet in length. The oil passes from the upper bank of the four inch tubes to the lower bank through nipple 8, and connection 9. From the last tube 10, of the heating element, the hot oil under pressure passes by means of a U-bend 11, into a vapor chamber 12. This vapor chamber 12 in the present instance, comprises four tubes each of 10-inch internal diameter and 20 feet long, connected to each other by means of yokes. The generated vapors pass out.

. through the risers or standpipes 18 to a com mon header 14. The risers 13 in the present instance take the forni of four inch pipes and Ts respectively. To the header 14 are connected two vapor lines which in the present instance are pipes of 10-inch internal diameter and some 2O or more feet long. These vapor lines 15 slope upwardly from the header 14 as shown clearly in the drawings. That portion of the vapors which condenses in the vapor lines 15 and header' 14 is returned as reflux condensate by means of the pipe 16, which is of substantially four inch diameter, to the inlet pipe 7, the arrangement being such that the reflux condensate is mixed with the fresh charging oil and is retreated in the heating element referred to.

Carbon or other solid material, such as pipe scale or iron sulphide, mechanically carried over with the vapors may be precipitated into the tube leg 17, which serves as a trap for this purpose. The liquid residue in hc vapor chamber is drawn off through a swedge nipple 18, which leads to outlet line 20. A throttle valve 19 is interposed iu the line 2O and serves as an emergency valve. In normal operation this valve 19 is open. The piper 20 is connected to a residuuni cooler 42. and at the outlet side of this cooling coil is a throttle Valve 43. We also preferably provide an auxiliary drawoi pipe 21, having valve 21a, Whlch is connected to an auxiliary residue cooler 44, controlled by throttle valve 45. The auxiliary dravvoif line and cooler are used in the yevent that the first drawof line or cooler becomes clogged or stopped up With carbon.

It is desirable to carefully regulate the temperature ofthe oil in the heating coil. We may place a pyrometer 22 in the upper bank of the heating coil, and also pyrometers 23, in the U-ll, to register the temperature of the liquid it is being transferred from the heating zone to the vapor chamber. Pyrometers 24 show the temperature of the vapors passing out ofthe vapor chamber. These pyrometers may be of the recording type desired.

It is desirableto prevent any of the reflux condensate from falling back into the vapor chamber. To this end the pipes 13b which lead from the risers to the header 14, slope downwardly toward the header, as shown clearly in Fig. 3. That portion of the vapors which are not condensed by the time they pass through the vapor lines 15 are conveyed through pipe connection 25 to water condenser' coil 26, in condenser box 27. The distillate, together with uncondensible gases, passesinto the receiver 28 through valve 29. This valve 29 is open in normal operation and acts as an emergency valve. The receiver is provided with liquid drawo' 29', having control valve 30, and is also provided with gas outlet 34, having control valve 35. The preslsure is regulated by suitably controlling the valves 30 and 35. A meter 31 is interposed in the drawoif 29. We also provide a sample dravvoif line controlled by valve l32.

We have heretofore stated that the reiux condensate passes from the header 14 through pi pe 16 to the inlet pipe 7. More specifically this is accomplished as follows: The reiux condensate passes out of the header 14 to pipe 36, thence to connection 38, to pipe 39. The reflux condensate from the vapor lines 15 passes through pipes 15', into the connection 38, and thence to the pipe 39 above referred to.

The pipe 39 in turn connects to the pipe 16.v

Carbon and scale traps 37 are also provided as shown more clearly in Fig. 3. A11 emergency valve 41is also inserted in the pipe 16. lngorder to determine the level of the liquid in the vapor chamber, We provide the superimposed try-cocks 46, which are connected by pipe 47, to cooler 48, having drawoif valve 49. There is a set of these try-cocks and associated condenser at various parts of the system wherever it is desired to take samples of hot oil. Y

We will now describe the general operation ofthe process'prior to describing the detailed operation of specific runs.

The 4-inch heating coils and 10-inch ex ansion chamber are charged with the fue oil to be treated, by means of a pressure pump such as a triplex Gould pump, until the level of the oil in the 10-inch expansion chamber is one-half of its diameter. The 4-incl1 tubes are full of oil before the furnace is fired. Before charging the 4-inch tubes and lO-inch expansion chamber with oil to be cracked, the residuum oil drawofl is closed. The uncondensible gas control valve and the pressure distillate receiver control valve are also closed. The entire apparatus is a closed one with all parts of same being in free communication with one another. The 4-inch heating tubes and 10inch expansion chamber having been charged with 340 gallons of the fuel oil to be treated, the portion of oil in the 4-inch heating tubes, is now subjected to heat by means of the burners set Within the Dutch oven of the furnace. After heating the oil in said 4-inch tubes for a period of an hour orso, the transfer liquid from the 4-inch heating tubes to the expansion chamber reaches a temperature of approximately 400 F. The triplex raw oil charging pump is then started and the raw oil is circulated through the 4-inch heating tubes into the expansion chamber back to the storage tank, from which it is again drawn by the pum The furnace fires are increased progressively as the furnace heats up so that the rapidity of heating the full raw oil is increased as shown by the temperature recording instrument set in the transfer liquid line from the 4-incl1 heating tubes to the 10-inch expansion chamber. The hydrocarbon vapors Within the apparatus exert their vapor pressure upon the liquid of the oil in said apparatus until it reaches the predetermined operating pressure desired, which, in the tests submitted ranged from 105 to 135-pounds per square inch. The

operation pressure is reached two to three hours before the normal pressure distillation of cracking takes place. Although the temperature of the transfer liquid has reached the desired temperature of cracking, the expansion chamber which is insulated, the risers from said expansion chamber, the lower manifold and vapor lines leading to the water condenser are not in temperature equilibrium With the temperature ofthe transfer liquid passing from the 4-inch heating tubes to the expansion chamber so that high Baume gravity pressure distillate dribbles over for several hours before actual full stream pressure distillation takes place. The full stream pressure distillation does not take place until the entire apparatus is in thermal equilibrium with the different parts of the system.

The pressure distillate oil is collected in a receiver having a control valve, and the pressure distillate leaving the receiver is metered as it passes to a storage tank and there gauged. The raw oil gauged into the apparatus is metered so that a definite amount of said raw oil passes into the appa.-

ratus in unit time. The residual oil leaving the expansion chamber passes to a storage tank where it is gauged, as we have found up to the present time that no meter will give the quantity of residual oil correctly, due to the amount of suspended c'arbon therein resulting from the cracking reaction. The permanent or uncondensible gases resulting from the thermal and pressure treatment of the oil are controlled by means of a valve, so that a constant, fixed pressure may be maintained upon the apparatus and said permanent gases are metered and give an indirect measure of the amount of cracking taking place in unit time. The generated vapors from the expansion chamber passing by means of risers to a header connected with vapor lines condense in partto a liquid and said liquid condensate does not pass back into the expansion chamber but is diverted by means of piping back into the l-inch heating tubes set within the furnace.

The control factors involved in the thermal and pressure distillation in the apparatus used are (l) pressure, (2) temperature, (3) rate of fuel oil into the system, (4) rate of pressure distillation formation, (5) rate of residual oil formation, (6) permanent or uncondensible gas formation.

The control of pressure upon the apparatus is the simplest factor involved in cracking. The pressures of the four tests submitted range from 105 to 135 pounds per square inch.

vThe temperatures of the various parts of the apparatus must be in equilibrium with one another for maximum production of pressure distillate oil in unit time. The temperature of the transfer liquid from the four inch heating tubes to the expansion chamber can be maintained relatively constant and offers no particular difficulty. The temperature of the residual oil leaving the expansion chamber can be maintained at the degrees F. desired as it is clearly a function of the temperature of the transfer liquid. The temperatures of the lower manifold attached to the vapor lines going to the Water condenser and the temperature ofthe vapors passing into the water condenser are more difficult of control due to fluctuating weather conditions affecting markedly the amount of condensate which refluxes back into the heating zone to be subjected to another cycle of operation. However, when weather conditions are static the temperature of the vapors passing into the water condenser can be controlled within'a few degrees F.

The control of the amount of fuel oil fed into the system per unit time may be maintained at the rate desired, for it is sometimes found necessary to change the rate of fuel oil going into the apparatus as a function of the changing weather conditions during an operating period, for fluctuating weather conditions, such as wind, and rain, following upon a static condition of the atmosphere increase greatly the amount of reflux condensate which passed back into the heating zone. It is then necessary to cut down the amount of fuel oil pumped into the heating zone during the period when excess reflux condensation takes place. To overcome this excess of-reiiux condensate the furnace fires can be increased to take care of this t relatively cool reux condensate which is going back into the system. However, by increasing the furnace temperature or the quantity of British thermal units passing into the furnace in a given time, allows the normal amount of pressure distillate to pass over into the receivers. But we have found it more advantageous to cut down the quantity of fuel oil passing into the apparatus in unit time so as to offset inclement weather conditions. By cutting down the amount of fuel oil going into the apparatus during such weather conditions, an excessive furnace temperature is avoided and the consequent excess carbon deposition in the four inch tubes and fire hazards are cut to a minimum.

The rate of pressure distillate formation and the gravity of same is a function of the amount of cracking taking place in unit time. The Baume gravity of the pressure distillate may be varied at will and dependent upon the market demands of the quality of the gasoline, kerosene, and gas oil resulting fromI the redistillation of the pressure distillate. The quality of pressure distillate can be controlled between 48 and 52 Baume, quite readily although it may vary between the wide limits of 42 to 80 Baume gravity. The amount of pressure distillate taken off per hour may range between 40 and 65 percent. although during some operating hours as high as percent of the raw oil going into the system in one hour can be taken ofi' as pressure distillate, but the quality is low.

The rate of flow per hour of residual oil passing out of the expansion chamber is dependent upon how much pressure distillate oil is taken off. It has been found that when a high percentage of pressure distillate oil is takenof that the residual oil becomes very heavy and viscous and precipitates an inordinate amount of carbon and pitch in the expansion chamber. In this particular apparatus this feature is not desirable for it is our desire to flood out the carbon in a colloidal condition in the residual oil and utilize it as such for fuel purposes, for the B. t. u. content per pound of such an oil is high, due to the suspended and colloidal character of the carbon dispersed through the oil. The permanent or uncondensable gases formed during the cracking reaction are indicative of the extent of the cracking of the iti pitch out of solution in the residuurn oil;

or that the cracking reaction takes places progressively to pitch hydrocarbons before carbon is actually formed, for upon opening the expansion chamber it was notedthat layers of carbon built up from the lower side had slight amounts of pitchy material between the interstices of the honeycomb structure.

Many stalactites of pitch and carbon which were brittle, containing oily material Were found on the upper portion of the expansion chamber. lhe stalactities had a relatively high melting point. lhe carbon was easily removed from the expansion chamber in slabs having the forni of the L18-inch expansion tubes, leaving no adhering hard carbon attached to the Wal-ls of the expansion charnloer. lin the tests submitted practically all of the carbon was deposited in the expansion chamber wherein it Was readilyreinoved at the end of a run. The carbon formed is a function of the amount of oil cracked and varies withinA very vvide liniits, for a gas oil from a mid-continent held or eastern field produced very niuch less carbon per gallon of ravv oil cracked comparative to residual or fuel oils. ln the runs submitted the pounds of carbon per gallon of fuel oil treated ranged between 0.21 to 0.29 pounds.

We will now describe the detailed operating condition andresults obtained in treat-` ing' certain specific charging stocks. 'lfhe charging stock in the first run was Wayside fuel or petroleum tar; in the second run a petroleum tar obtained from the mixture of Augusta-and lllbing crudes; the third run from Delaware petroleum tar; and the fourth a mixture' of 50 percent of theviaugusta-Filling blend and per cent of W ayside.

rlhe Wayside fuel oil Was of 23.6 Baume gravity represented 72.3 per cent of the crude petroleum oil. 'l`he normal gasolene yield of 53-5fl Baume gravity in the Wayside crude petroleum is 17.4 per cent. By cracking this 72.3 per cent of Vlayside fuel oil under heat and pressure 13.8 per cent of 58 Baume gravity gasolen'e Was produced on the basis of the crude petroleum. By cracking the fuel oil fraction of the crude petroleum M an additional i5 per cent of gasoline was produced on the basis of the crude petroleum over that which was present in the crude oil as it caine from the well.

The average operating conditions of the run while on pressure distillation were: pressure 105 pounds; furnace temperature 1G00 degrees F.; the transfer liquid from the heating tubes to the expansion chamber was 850 degrees F., and the residual cil leaving the expansion chamber 7T 0 degrees F. The aerial temperature average 573 F. The gat lons of raw oil fed into the cracking appa ratus over a period of 35 hours ou pressure distillation was 218.7 gallons per hour, the average gallons of pressure distillate 4of 43.2 Baume gravity, per hour was 94.9, While 111.9 gallons of residual oil of 19.6 gravity Was producedhourly.

rlhegasolene production per hour on ressure distillation was 421.3 gallons, while erosene showed 24.6 gallons and the gas oil also showed 24.6 gallons per hour.

Upea dialling uit Wayside nai @u at atmospheric pressure down to coke the yield was 8.1 per cent on a Weight basis ofthe fuel oil. Upon subjecting this sarne fuel oil to heat and pressure, Z656 gallons of fuel produced 2100 pounds of dry carbon, which calculates against the oil treated on a Weight basis 3.6 per cent. This fuel oil is a heavy carbon forming oil, but in this apparatus the deposition is so controlled 'that practically all of it deposits in the expansion chamber away from the heating zone Where no hot spot formation is possible. rlhe carbon in the expansion chamber Was of a highly por ous character, light, and occupied a relativa ly large volume of space for its weight conrparative to carbon formation when a midi# continent oil is cracked under heat and pressure under similar conditions of treatment. In the second run the fuel oil resulting from the atmospheric pressure distillation` of the Augusta and Flbing titans.) held represented 552 per cent of the crude petroleiun oil. This crude petroleum oil, upon atinospheric distillation in ordinary crude stills, produced 17 .1 per cent of 5d aulne gravity gasolene. By cracking the 55.2 of 2li-.3 Baume gravity fuel oil, the yield of gasolene calculated against the crude oil was increased 16.3 per cent, or per cent additional gasolene lwas produced by cracking, over that which was normally present in the crude oil to sta with.

'llhe operating conditions, as an average, were as follows: lhe pressure vias 120, the furnace temperature 16250 F., the transfer liquid from the heating zone to the expansion chamber was 3570 F., While the resi ual oil showed 'i620 F., and the redux 647 F., While the manifold liquid showed 790 F., and the aerial temperature 586 F.

rl`he average gallonage of raw oil fed into the system per hour over a period of 251/2 iid hours, on pressure distillation, showed 204 gallons, producing therefrom 119.1 gallons of pressure distillate of 49.2 Baume gravity and? 3.5 gallons of residuum oil of 16.4 Baume gravity. @n pressure distillation, the gasolene produced Was 60 gallons per hour, heroserie 16.9 gallons and 40 gallons of gas oil, as an average, per hour.

The Augusta-Ehling-Kansas :field fuel oil, upon distillation at atmospheric pressure to dry coke, yielded 6.7 per cent on a weight basis of the oil. Upon cracking, the fuel oil, at an average pressure of 120 pounds and transfer liquid from the heating zone to the insulated expansion chamber of 85T degrees. yielded 2.8 per cent of carbon on a weight basis against the fuel oil cracked. The condition of the carbon in the expansion chamher, where the bulk of it Was deposited, was of a honeycomb structure interspersed with pitchy hydrocarbon material, and quite black in color, and with Widely dilferent characteristic properties than the grayish carbon formed from the atmospheric distillation to coke. lil/'hen the carbon resulting from the cracking reaction is treat-ed with carbon bisulphide to extract whatever' oil or solid hydrocarbons which may be present, the carbon shows a lampdalach, light product, and of a more or less velvety black color.

rlhe following disclosures cover the details of the third run on a Delaware Ulrlahomr. fuel oil of 21.6 Baume gravity and represents lll.2 per cent of the Delaware crude petroleum. rlhis Delaware petroleum, upon normal distillation, yielded 18 per cent of gasoline. By cracking the fuel oil, after topping olf the gasoline, kerosene and gas oil by ordinary distillation, an additional i3 per cent of gasoline was produced on the basis of the crude oil. By cycling the fuel through the apparatus once, the normal gasoline content of the crude oil veas increased 75 per cent over that which was present as it .left the Well.

The average operating conditions of the run were: pressure, 130 pounds; furnace temperature, 16530 `ransfer liquid from. the heating sone to the expansion chamber, 84Go it.; residual temperature, 7550 and. vapor temperature, fi-57 F., the above values being the averages while on pressure distillation. llhe fuel oil average per hour was 2387 gallons during 21 hours of pressure distillation; which yielded, under heat and pressure, 138.5

of a 48.8 gravity pressure distillate and 78 gallons of ay residuum oil of 1%.() Baume gravi Ehe gasoline production per hour, While o pressure distlllation of 21 hours, was

i *.1 With-the gallonage `or 18.3 for heros-ene and 37.9 for gas oil.

When the Delaware fuel oil Was distilled to dry colle at atmospheric vncssnre, the per cent. of carbon was c fuel oil, on Weight basis. this fuel oil assess? 23.8 was treated under presure distillation over a period of .l5 hours and 'l5 minutes. treating, as an average of said fuel oil 3625.5 gallons per hour during that period of time. 'l`he pressure distillate averaged 200 gallonsl per hour of 46 Baume gravity and 1111.8 gal lons of 15.6 gravity residuuin oil.

The gasolcne production per hour on pressure distillation Was 9() gallons, while .rorosene was 50.2 gallons and 5%.1 gallons of gas oil per hour were recovered.

The operating conditions were: pressure, 135 pounds; furnace temperature, 16d-(O lV.; transfer liquid from the heating zone to the c.\pansion chamber was 829O lf., the residuum oil leaving the expansion chamber showed an average of (84.0 lf., While the vapor temperature averaged 5930 l".

The per cent of carbon was 7.4 on a weight basis when the fuel oil was distilled to dry colic at atmospheric pressure. Upon prf. distillation or the -fuel oil, 2.83 per cent resulated on a Weight basis against tne oil treated. rlhe carbon in the expansion cham-- ber was of a porous, honeycomb structure interspersed with pitchy hydrocarbon material. i

W e claim as our invention 1. A.. continuous process for cracking 'nydrocarbons, consisting in conducting a stream of hydrocarbons through a heating zone.

where a cracking temperature in excess of 800O l?. maintained, in discharging the highly heated stream of hydrocarbons into a separating chamber and depositing the ar bonaceous residue in said chamber, in mainn taining the contents of said separating cliainher at a temperature lower than that of said. heating zone, but sufiiciently high to cause free evaporation of the relatively low i'ioilin;T point liquids introduced thereto, in renier ing the carbonaceous residue from said scparating chamber., in discharging the vapors from said separating chamber and passing the same to a reflux condensing zone, in precipitating solid and colte-lille particles entrained with the vapors therefrom, prior to their introduction to the rcllux condensing Zone, in permitting precipitation of addi tional colte-like and solid particles from the refluxcondcnsate separated from the vapors` inthe reflui; condensing Zone. in returning llal reflux condensate, free from such col e-lihc and solid particles, to said stream of hydro cai-bons flowing through the heating anne, and in continuously transmitting the mixed sure 1,8sae27 hydrocarbons through said heating zone and into s aid separating chamber.

2. A continuous process for cracking hy-i drocarbons, consisting in conducting a stream of hydrocarbons through a heating zone, Where a cracking temperature in excess of 800 F. is maintained, in discharging the highly heated stream of hydrocarbons into al separating chamber and depositing the carbonaceous residue in said chamber, in maintaining the contents ot'said separating chamber at a temperature lower than that of said heating zone, but sufiiciently high to cause free evaporation of the relatively low boiling pointlliquids introduced thereto, in removing the carbonaceous residue from ysaid separating chamber, in discharging the vapors from said separating chamber and passmg the same to a reflux condensing zone, in precipitating solid and coke-like particles entrained with the vapors therefrom,'prior to their introduction to the reflux condensing zone, in precipitating additional coke-like and solid particles from 'the .reflux condensate separated from the vapors in the reflux condensing zone, in returning the reflux condensate, free from such coke-like and solid particles, while at a temperature in excess of 550 F., to said stream of hydrocarbons flowingv through the heating zone, in continuously transmitting the mixed hydrocarbons through said heating zone andinto ,said separating chamber. l

3. A process'for cracking hydrocarbons, which consists in conducting a stream of hydrocarbons through a heating zone, where a cracking temperature is maintained, in discharging the resultant `highly heated stream of hydrocarbons into a separating chamber and depositing `the carbonaceous residue in said chamber, in maintaining the contents of said separating chamber at a temperature lower than that of said heatingv zone, but sufliciently high to cause free evaporation of relatively low boiling point liquid from the carbonaceous residue, in removing the carbonaceous residue as it accumulates in said chamber and discharging it from' the system, in discharging vapors in an upward direction from said separating chamber to-a reflux condensing zone, in the precipitating coke-like and solid particles entrained with the vapors passed from the separating chamber to the reflux ycondensing zone, prior to the admission of the vapors to the reflux condensing zone, in condensing the high boiling point fractions from the vapors in the reflux condensing zone, in returning the reflux condensate, free from solid and coke-like particles entrained with the vapors passing from the separating chamber to the reflux condensing zone, and mixing the same with the chargliquid constituents therein, in removing the carbonaceous residue from sald separating chamber, in discharging the vapors from said separating chamber and in passing the same to a reflux condensing zone, in removing from the path of the vapors liquid condensed from the vapors during their passage from the separating chamber to the reflux condensing zone, together with such solid and coke-like particles as are precipitated from the vapors and preventing such liquid and coke-like particles from entering the reflux condensingy zone, in returning reflux condensate separated rom the vapors and mixing the same with additional charging stock and continuously transmitting the mixture through said heating zone and into said separating chamber. t

GUSTAV EGLOFF. HARRY P. BENNER.

ing stock passing through said heating zone,

and in continuously transmitting the mix- 

